Post COVID-19 fitness to dive assessment findings in occupational and recreational divers.

INTRODUCTION: It is now known that COVID-19 has long term effects that may not correlate with clinical severity of disease. The known pulmonary and cardiovascular changes as well as thrombotic tendency could predispose to diving accidents. We aimed to investigate COVID-19 related changes that may cause disqualification from diving among divers who recovered from the disease. METHODS: Occupational and recreational divers who applied for fitness to dive (FTD) assessment after COVID-19 infection were included. Routine FTD assessments were performed. Details of COVID-19 history were evaluated. Lung computed tomography (CT) scans were advised if not previously performed or if there were COVID-19 related changes in previous scans. Divers with pathological findings were restrained from diving and followed prospectively. RESULTS: Forty-three divers were analysed. Thirteen divers were restrained from diving, all due to persistent COVID-19 related changes in lung CT. The prevalence of CT with at least one lung lesion was 68.2% at the time of diagnosis, 73.3% in the first three months after diagnosis and 19.2% later. The most common CT findings were glass ground opacities and fibrotic changes. Demographic characteristics and COVID-19 history of divers deemed 'unfit' were similar to those deemed 'fit'. CONCLUSIONS: Divers who recover from COVID-19 should undergo FTD assessments before resuming diving. A chest CT performed at least three months after diagnosis may be suggested.

A COVID-19 infection incidentally detected during hyperbaric oxygen treatment and preventive measures for COVID-19 transmission in a multiplace hyperbaric chamber.

INTRODUCTION: SARS-CoV-2 (COVID-19) was declared a global pandemic on 11 March 2020 and has become a serious threat to public health. As it can easily be transmitted through droplets and aerosols, there is an increased risk of transmission in enclosed environments such as hyperbaric oxygen treatment (HBOT) units if preventive measures are not taken. CASE REPORT: A 16-year-old female tested positive for SARS-CoV-2 during HBOT for idiopathic sudden sensorineural hearing loss. The other patients and the inside attendant who attended the sessions with her were regarded as contacts, tested for SARS-CoV-2, and quarantined until the test results were available. Ultimately, none of them tested positive. DISCUSSION: As HBOT in multiplace chambers entails a high risk of SARS-CoV-2 transmission, we strictly adapted our practice to consider that every patient could be a potential asymptomatic carrier. Therefore, the negative results of all contacts in this case and the fact that no confirmed cases of COVID-19 were reported suggests that these measures successfully prevented SARS-CoV-2 transmission in our HBOT clinic. SARS-CoV-2 transmission can be prevented if sufficient protective measures are taken.

The evaluation of in-chamber sound levels during hyperbaric oxygen applications: Results of 41 centres.

INTRODUCTION: Noise has physical and psychological effects on humans. Recommended exposure limits are exceeded in many hospital settings; however, information about sound levels in hyperbaric oxygen treatment chambers is lacking. This study measured in-chamber sound levels during treatments in Turkish hyperbaric centres. METHODS: Sound levels were measured using a sound level meter (decibel meter). All chambers were multiplace with similar dimensions and shapes. Eight measurements were performed in each of 41 chambers; three during compression, three during decompression, and two at treatment pressure, one during chamber ventilation (flushing) and one without ventilation. At each measurement a sound sample was collected for 25 seconds and A-weighted equivalent (LAeq) and C-weighted peak (LCpeak) levels were obtained. Recorded values were evaluated in relation to sound level limits in regulations. RESULTS: The highest sound level measured in the study was 100.4 dB(A) at treatment pressure while ventilation was underway and the lowest was 40.5 dB(A) at treatment pressure without ventilation. Most centres had sound levels between 70 dB and 85 dB throughout the treatment. Ventilation caused significant augmentation of noise. CONCLUSIONS: The chambers were generally safe in terms of noise exposure. Nevertheless, hyperbaric chambers can be very noisy environments so could pose a risk for noise-related health problems. Therefore, they should be equipped with appropriate noise control systems. Silencers are effective in reducing noise in chambers. Thus far, hyperbaric noise research has focused on chambers used for commercial diving. To our knowledge, this is the first study to investigate noise in hospital-based chambers during medical treatments.

Pulmonary barotrauma during hookah diving: a case report.

When commercial sea harvesters have dive accidents, it is sometimes difficult to obtain an accurate dive history and make a definitive diagnosis. We report a sea harvest diver who dived to collect sea snails (Rapana venosa) by using a hookah dive system. He experienced mediastinal and subcutaneous emphysema due to interruption of breathing airflow. Thoracic computed tomography performed one year prior to the accident revealed paramediastinal subpleural blebs on both lung apices. Emphysema was resolved by administering normobaric oxygen.

Incidence of decompression sickness in hypobaric hypoxia training.

Simulated flight in a hypobaric chamber is a fundamental component in the physiological training of aviators. Although rare, there is always a risk of decompression sickness (DCS) in trainees during hypobaric hypoxia training. In this study we aimed to determine the incidence of altitude-induced DCS and the symptoms manifested in trainees and inside chamber observers (ICOs) during the training sessions. We retrospectively reviewed the records of DCS cases during the period of January 1, 2011, and October 1, 2018. The records of 6,657 trainees and 615 ICOs were evaluated. The gender distribution in 6,657 trainees was 6,578 (98.81%) male and 79 (1.19%) female. The numbers of DCS cases in trainees and ICOs were six (0.09%) and two (0.33%), respectively [(ICOs versus trainees - odds ratio (OR): 3.574; 95% CI 0.720-17.744; (p > 0.05)]. All ICOs were male; no DCS incident was observed among female trainees. Recompression treatments were applied on site, and complete recovery was achieved in all cases. Overall DCS incidence was found to be 0.11% among the 7,193 male subjects, which included trainees and ICOs. The higher incidence of DCS in ICOs was attributed to the physical activities performed at altitudes by ICOs. In such training, established instructions have to be strictly followed by physicians, ICOs and trainees. All trainees and ICOs should be aware of the symptoms and signs of DCS, and medical support including a recompression facility, should be provided on site during hypobaric hypoxia training.

Protective effect of hyperbaric oxygen treatment on rat intestinal mucosa after mesenteric ischaemia and reperfusion.

INTRODUCTION: Mesenteric ischaemia results from a lack of adequate blood flow to and oxygenation of the mesentery and intestines. The aim of the present study was to evaluate the effect of hyperbaric oxygen treatment (HBOT) on the healing process in intestinal mucosa of rats undergoing mesenteric ischaemia and reperfusion. METHODS: Thirty-two Wistar-Albino rats were divided into four groups of eight: 1) ischaemia/reperfusion (I/R); 2) sham operation; 3) I/R+HBOT started 6 hours after reperfusion; 4) I/R+HBOT started 12 hours after reperfusion. In the I/R groups, a vascular clamp was placed across the superior mesenteric artery to occlude arterial circulation for 60 minutes, followed by reperfusion. A dose of HBOT consisted of 100% oxygen breathing for 90 minutes at 2.5 atmospheres absolute pressure. Thirteen doses of HBOT were administered after ischaemia. The rats were sacrificed on the eighth day, and their intestinal tissues were harvested for histopathologic analysis. The tissue levels of catalase, malondialdehyde, and glutathione were determined. RESULTS: The histopathological scores (HSCORE) were consistent with macroscopic examinations. The scores were significantly higher (worse) in Group 1 compared to Group 2, Group 3, and Group 4 (for all comparisons, P < 0.05). Group 4's HSCORE was significantly higher than those of Group 2 and Group 3 (for both comparisons P < 0.05). Group 3's HSCOREs were only marginally higher than Group 2. Group 3 exhibited higher glutathione levels than Group 1 (P < 0.05). There were no significant differences across the groups with respect to malondialdehyde and catalase levels. CONCLUSION: A beneficial effect of HBOT was observed on oxidative stress and inflammation in acute mesenteric ischaemia-reperfusion.

Evaluation of fatal diving accidents in Turkey

In any kind of diving there is a risk of accidents, as the move from the topside environment to underwater can affect a diver's physiological and psychological condition. It is important to investigate dive accidents to clarify the causative factors and determine preventive measures. In this study, autopsy files of fatal dive accident cases were reviewed to evaluate demographic data, type of diving, purpose of dive, seasonal distribution, autopsy findings, and causes of death. We reviewed 56 fatal dive accident files from autopsy units in cities where dive activities are concentrated and from the archive of the Turkish Underwater Federation. Four cases were excluded from the study since we were unable to obtain autopsy reports. Of 52 cases there were 20 scuba divers, two surface-supplied divers and 30 breath-hold divers. The majority of cases involved males (94%). The average age of 50 cases was 38.6; age estimation for two cases could not be determined due to advanced putrefaction. Of these fatal dive accidents 75% took place over a period of six months between May and October. Drowning was recorded as the primary cause of death in these cases. X-ray imaging was used in four (8%) cases. A special autopsy technique was used for nine (17%) cases, to detect possible pulmonary barotrauma and arterial gas embolism. The forensic specialist who is planning to conduct the autopsy for a dive fatality should have knowledge and experience about dive physics and physiology as well as physiopathology of dysbaric injuries.

Eurasian Tunnel Project: the first saturation dives during compressed-air work in Turkey.

The Eurasian Tunnel is a 5.64-km crossroad tunnel that connects Europe and Asia. Located under the seabed for the first time, 3.34 km of the tunnel that crosses the Bosphorus was built by advanced tunneling techniques. An exclusively designed tunnel boring machine (TBM), which has an operating pressure of 11 bars and a diameter of 13.7 meters was used for boring the seabed tunnel. The deepest point was 106 meters below sea level. One bounce diving period and seven saturation diving periods were needed for the repair and maintenance of the TBM during the project. Total time spent under pressure was 5,763 hours. A saturation decompression chamber for four divers was used for the saturation interventions, and divers breathed trimix at storage and excursion depths. The longest saturation run was the second, with storage at 10 bars and excursions to 10.4 bars. Twenty-three professional divers who were all experienced in compressed-air work were assigned to work on the project. Four dive physicians provided medical support, which included screening of divers before and during the hyperbaric interventions as well as on-site supervision. There were no diving-related accidents. A minor hand trauma, an external otitis and occasional insomnia were non-diving-related health issues that occurred during saturation and bounce diving. To our knowledge, the Eurasian Tunnel was the first project to perform TBM repair operations at such depths under the seabed and the first saturation diving in Turkey. In this report, we aimed to share our experiences of hyperbaric medical consulting in support of this type of tunneling project.

Hyperbaric oxygen therapy for five days increases blood-brain barrier permeability.

This study aimed to explore the effects of hyperbaric oxygen (HBO2) on blood-brain barrier (BBB) integrity in rats, when administered for one (at 2.5 ATA, 3 HBO2 sessions a day) and five days (at 2.5 ATA, 3 HBO2 sessions a day for the first two days, and twice a day for the last three days). Horseradish peroxidase (HRP) was used to evaluate the BBB permeability. Superoxide dismutase (SOD) activity, glutathione (GSH) and malondialdehyde (MDA) levels were measured in the cerebral cortex and hippocampus regions. Frequent vesicles containing HRP reaction products were observed in capillary endothelial cells in the cerebral cortex and hippocampus of rats subjected to HBO2. The accumulation of HRP reaction products in these brain regions was significantly higher than that of control animals (P ⟨ 0.01). In animals that received HBO2, MDA levels (P ⟨ 0.01 for five days) and GSH (p ⟨ 0.05 for one day, and P ⟨ 0.01 for five days) were decreased in the cerebral cortex, whereas SOD activities slightly increased in this region. In animals that received HBO2 significant decreases in MDA (P ⟨ 0.05 for one day; P ⟨ 0.01 for five days) and GSH (P ⟨ 0.05 for five days) levels were observed in the hippocampus region, but SOD activities decreased in this region. We showed that HBO2 administered with the doses described above impaired BBB integrity in otherwise healthy rats. Therefore, we suggest that the results of this study should be taken into consideration when patients are exposed to HBO2 with the same doses.

Acute and long-term effects of hyperbaric oxygen therapy on hemorheological parameters in patients with various disorders.

Inhalation of 100% oxygen in a hyperbaric chamber has been accepted as a useful treatment for patients with various pathologies who suffer from hypoxia. The oxidative effects of hyperbaric oxygen (HBO) on RBCs have been investigated in animals but there is not enough data on hemorheological parameters in patients following HBO treatment (HBOT).In this study, we investigated the effect of HBO on hemorheological and haematological parameters during treatment. Red blood cell (RBC) deformability and aggregation, blood and plasma viscosity and superoxide dismutase activity were investigated in patients who underwent HBOT. Hematological parameters were determined by an electronic hematology analyzer. A Laser-assisted Optical Rotational Cell Analyzer (LORCA) was used to measure RBC deformability. RBC aggregation was measured for cells in autologous plasma and for cells resuspended in PBS containing Dextran70 (3% ) by using a Myrenne Aggregometer. A Wells-Brookfield cone/plate rotational viscometer was used for viscosity measurements. According to our results, a significant decrement of the hematocrit and the RBC count was observed after the 20th session of HBOT compared to the baseline, but none of the hemorheological parameters changed significantly. Our results showed that HBOT did not cause any significant changes in hemorheological parameters, thereby not representing any problems for the patients.

Effect of hyperbaric oxygen treatment on pilonidal disease surgery.

Surgical excision and lay-open is a well-known technique for the treatment of sacrococcygeal pilonidal disease, which impairs a patient's quality of life considerably since wound healing takes a substantial amount of time. It is known that with this method total healing period is longer, but recurrence rate of the disease is lower. The beneficial effects of hyperbaric oxygen (HBO2) therapy on wound healing have been well established since it was first put into in clinical use. The purpose of this prospective randomized clinical trial was to investigate the effects of HBO2 therapy on wound healing in the patients who had sacrococcygeal pilonidal disease and surgical treatment. Total epithelialization times of 12 patients (Group 1) who received surgical intervention were compared with those of 10 patients who had surgical intervention and HBO2 therapy (Group 2). In both groups excised tissue volume, excised skin area, body mass index, blood hemoglobin, albumin levels, ages and duration of the complaints were recorded and there was no statistically significant difference in these parameters except albumin levels when compared. The complete epithelialization time was significantly shorter in Group 2 (50 ± 11 vs. 83 ± 18, p⟨0.001). We conclude that HBO2 had beneficial effects on wound healing, in the patients who had sacrococcygeal pilonidal disease and were treated with surgical excision applying lay-open technique.

Decompression sickness cases treated with recompression therapy between 1963 and 1998 in Turkey: review of 179 cases.

The purpose of this study was to review the cases diagnosed as decompression sickness (DCS) with recompression therapy treament between 1963 and 1998 in Turkey. The records of 179 cases were analyzed for age, gender, type of DCS, presenting signs and symptoms, time to onset of symptoms, time to recompression therapy, recompression table used, total number of treatments and outcomes. The diving depth on the day of injury ranged between 60 and 215 fsw (18 and 65 msw). The symptoms developed during ascent or within 10 minutes after surfacing in 47% of divers and within the first hour in 87% of the divers. The most frequent symptom was sensory loss in the extremities. The dive before the symptoms was a repetitive dive in 50% of the cases and the diagnosis was Type II DCS in 79% of these divers. Most of the divers (84%) received recompression therapy after a delay of more than 12 hours. Healing rate was 68% with the air recompression tables and 86% with the oxygen tables. Repetitive dives were associated with a higher incidence of Type II DCS than single dives (79% and 66%, respectively). The results using recompression tables with oxygen were more successful than the treatment with air tables.

Effects of topical nasal steroids and diclofenac on the nasal mucosa during hyperbaric oxygen therapy: a double-blind experimental study.

We aimed to evaluate nasal mucosal changes and efficiency of nasal steroids and diclofenac on nasal mucosa during hyperbaric oxygen (HBO) treatment. Forty adult Albino-Wistar rats were randomized into four groups. Group 1 (control group) (n = 10) not exposed to hyperbaric or enhanced oxygen concentrations; group 2 (HBO group) (n = 10) underwent only HBO treatment; group 3 (n = 10) received HBO and intranasal mometasone furoate (10 µl/day); group 4 (n = 10) treated with HBO and diclofenac sodium (10 mg/kg/day ip). Specimens of nasal mucosa were collected after sacrificing and dissection of animals. The specimens were processed for light microscopic evaluation, and then evaluated histopathologically for fibroblastic proliferation and inflammation. Regarding the scores of inflammation, the level of inflammation in the control group was significantly less severe than the other groups (p < 0.05). Evaluation of the fibrosis scores showed that the scores of both groups 2 and 4 were significantly increased (p < 0.05). There were no statistically significant differences between groups 2, 3, and 4 as for fibrosis and inflammation (p > 0.05). Chronic HBO treatment induced mild inflammation of the nasal mucosa. These effects cannot be prevented adequately by administration of nasal steroids and diclofenac.

Is combined therapy more effective than growth hormone or hyperbaric oxygen alone in the healing of left ischemic and non-ischemic colonic anastomoses?

OBJECTIVE: Our aim was to investigate the effects of growth hormone (GH), hyperbaric oxygen and combined therapy on normal and ischemic colonic anastomoses in rats. METHODS: Eighty male Wistar rats were divided into eight groups (n = 10). In the first four groups, non-ischemic colonic anastomosis was performed, whereas in the remaining four groups, ischemic colonic anastomosis was performed. In groups 5, 6, 7, and 8, colonic ischemia was established by ligating 2 cm of the mesocolon on either side of the anastomosis. The control groups (1 and 5) received no treatment. Hyperbaric oxygen therapy was initiated immediately after surgery and continued for 4 days in groups 3 and 4. Groups 2 and 6 received recombinant human growth hormone, whereas groups 4 and 8 received GH and hyperbaric oxygen treatment. Relaparotomy was performed on postoperative day 4, and a perianastomotic colon segment 2 cm in length was excised for the detection of biochemical and mechanical parameters of anastomotic healing and histopathological evaluation. RESULTS: Combined treatment with hyperbaric oxygen and GH increased the mean bursting pressure values in all of the groups, and a statistically significant increase was noted in the ischemic groups compared to the controls (p<0.05). This improvement was more evident in the ischemic and normal groups treated with combined therapy. In addition, a histopathological evaluation of anastomotic neovascularization and collagen deposition showed significant differences among the groups. CONCLUSIONS: Combined treatment with recombinant human growth hormone and hyperbaric oxygen resulted in a favorable therapeutic effect on the healing of ischemic colonic anastomoses.

Is combined therapy more effective than growth hormone or hyperbaric oxygen alone in the healing of left ischemic and non-ischemic colonic anastomoses?

OBJECTIVE: Our aim was to investigate the effects of growth hormone (GH), hyperbaric oxygen and combined therapy on normal and ischemic colonic anastomoses in rats. METHODS: Eighty male Wistar rats were divided into eight groups (n = 10). In the first four groups, non-ischemic colonic anastomosis was performed, whereas in the remaining four groups, ischemic colonic anastomosis was performed. In groups 5, 6, 7, and 8, colonic ischemia was established by ligating 2 cm of the mesocolon on either side of the anastomosis. The control groups (1 and 5) received no treatment. Hyperbaric oxygen therapy was initiated immediately after surgery and continued for 4 days in groups 3 and 4. Groups 2 and 6 received recombinant human growth hormone, whereas groups 4 and 8 received GH and hyperbaric oxygen treatment. Relaparotomy was performed on postoperative day 4, and a perianastomotic colon segment 2 cm in length was excised for the detection of biochemical and mechanical parameters of anastomotic healing and histopathological evaluation. RESULTS: Combined treatment with hyperbaric oxygen and GH increased the mean bursting pressure values in all of the groups, and a statistically significant increase was noted in the ischemic groups compared to the controls (p<0.05). This improvement was more evident in the ischemic and normal groups treated with combined therapy. In addition, a histopathological evaluation of anastomotic neovascularization and collagen deposition showed significant differences among the groups. CONCLUSIONS: Combined treatment with recombinant human growth hormone and hyperbaric oxygen resulted in a favorable therapeutic effect on the healing of ischemic colonic anastomoses. .

The effects of hyperbaric air and hyperbaric oxygen on blood-brain barrier integrity in rats.

Hyperbaric oxygen (HBO) treatment yields conflicting results on blood-brain barrier (BBB) integrity under various pathological conditions and the effects of HBO on healthy brain is poorly understood. In this experimental study, the effects of HBO on BBB integrity were investigated in comparison with hyperbaric air (HBA) in intact rats. Four sessions of HBA or HBO were applied to intact rats in 24h. BBB integrity was functionally and structurally evaluated by determining extravasation of Evans blue (EB) dye and horseradish peroxidase (HRP) tracers. In immunohistochemical evaluation, relative staining intensity for occludin, a tight junction (TJ) protein, and aquaporin 4 (AQP4), a water-channel protein, was detected in the barrier type of microvessels of brain by image analysis. BBB permeability to EB dye significantly increased in animals in HBO treatment group compared to those in HBA and control groups (p<0.05). The immunoreactivity of occludin, a tight junction protein, remained essentially unaltered in capillaries of hippocampus in all groups. In animals exposed to HBO, AQP4 immunoreactivity significantly increased in parietal cortex compared to those in HBA and control groups (p<0.01). Ultrastructurally, frequent vesicles containing HRP reaction products were observed in capillary endothelial cells in cerebral cortex and hippocampus of rats subjected to both HBA and HBO. Our results indicate that the HBO administration to intact rats increased BBB permeability to both EB and HRP while HBA increased only HRP extravasation in these animals. The results of this study suggest that HBA also impairs the BBB integrity in intact rats as well as HBO.

Effect of growth hormone, hyperbaric oxygen and combined therapy on the gastric serosa.

AIM: To investigate the role of growth hormone (GH), hyperbaric oxygen therapy (HBOT) and combined therapy on the intestinal neomucosa formation of the gastric serosa. METHODS: Forty-eight male Wistar-albino rats, weighing 250-280 g, were used in this study. The rats were divided into four groups (n = 12): Group 1, control, gastric serosal patch; Group 2, gastric serosal patch + GH; Group 3, gastric serosal patch + HBOT; and Group 4, gastric serosal patch + GH + HBOT. Abdominal access was achieved through a midline incision, and after the 1-cm-long defect was created in the jejunum, a 1 cm × 1 cm patch of the gastric corpus was anastomosed to the jejunal defect. Venous blood samples were taken to determine the insulin-like growth factor 1 (IGF-1) and insulin-like growth factor binding protein 3 (IGFBP-3) basal levels. HBOT was performed in Groups 3 and 4. In Groups 2 and 4, human GH was given subcutaneously at a dose of 2 mg per kg/d for 28 d, beginning on the operation day. All animals were sacrificed 60 d after surgery. The jejunal segment and the gastric anastomotic area were excised for histological examination. The inflammatory process, granulation, collagen deposition and fibroblast activity at the neomucosa formation were studied and scored. Additionally, the villus density, villus height, and crypt depth were counted and recorded. The measurements of villus height and crypt depth were calculated with an ocular micrometer. New vessel growth was determined by calculatingeach new vessel in a 1 mm(2) area. RESULTS: In the histological comparison of groups, no significant differences were observed between the control group and Groups 2 and 3 with respect to epithelialization, granulation, fibroblastic activity and the inflammatory process, but significant differences were present between the control group and all others groups (Groups 2-4) with respect to angiogenesis (P < 0.01) and collagen deposition (P < 0.05, P < 0.01). Significant differences between the control group and Group 4 were also observed with respect to epithelialization and fibroblastic activity (P < 0.01 and P < 0.05, respectively). There were significant differences in villus density in all of groups compared with the control group (P < 0.05). Crypt depth was significantly greater in Group 4 than in the control group (P < 0.05), but no other groups had deeper crypts. However, villus height was significantly longer in Groups 2 and 4 than in the control group (P < 0.05). The comparison of groups revealed, significant difference between control group and Groups 2 and 4) with respect to the levels of IGF-1 and IGFBP-3 (P < 0.01) 3 wk after the operation. CONCLUSION: HBOT or GH and combined therapy augmented on neomucosal formation. The use of combined therapy produced a synergistic effect on the histological, morphological and functional parameters.

Development of underwater and hyperbaric medicine as a medical specialty in Turkey.

Underwater and hyperbaric medicine focuses on diving physiology, prevention and treatment of health problems related to the exposure to high ambient pressure and therapeutic use of hyperbaric oxygen for several medical conditions. Adequate educational standards should be developed for physicians working in the field of underwater and hyperbaric medicine. In Turkey, underwater and hyperbaric medicine is one of the medical specialties. The history of underwater and hyperbaric medicine as a medical specialty is dated back to the 1960s. In this paper, we review standards and the development of underwater and hyperbaric medicine as a medical specialty in Turkey.

Pneumomediastinum or lung damage in breath-hold divers from different mechanisms: a report of three cases.

Normally pulmonary over-inflation is not an issue during breath-hold diving, in contrast to lung squeeze. Compared with compressed air diving, pulmonary barotrauma is rare in breath-hold diving. Several mechanisms can lead to an increase in intrathoracic pressure in breath-hold diving that may cause alveolar rupture. Here we report three cases of pulmonary barotrauma in breath-hold diving. Using high-resolution chest tomography, bullous damage in Case 1, and pneumomediastinum in Cases 2 and 3 were detected. Transient neurological symptoms in Cases 1 and 2 suggested cerebral arterial gas embolism. The mechanisms that caused intrapulmonary overpressure were, respectively, lung packing ('buccal pumping'), considerable effort and straining at depth, and breathing compressed air at depth and ascending without exhaling. All three cases recovered without specific treatment such as recompression.

Combination hyperbaric oxygen and temozolomide therapy in C6 rat glioma model.

PURPOSE: Temozolomide (TMZ) has anti-tumor activity in patients with malignant glioma. Hyperbaric oxygen (HBO) may enhance the efficacy of certain therapies that are limited because of the hypoxic tumor microenvironment. We examined the combined effects of TMZ-HBO in a rat glioma model. METHODS: After stereotactic injection of C6/LacZ rat glioma cells into the Wistar rats brain, the rats were randomly assigned to three treatment groups [group 1, control treatment; group 2, TMZ alone; group 3, a combination of TMZ and HBO]. Rats were sacrificed 18 days after treatment, and number of intra-/peri-tumoral vessels, microendothelial proliferations, immunohistochemistry and necrotic area were evaluated. RESULTS: Tumoral tissue was stained only sparsely with GFAP. Temozolomide treatment was significantly decreased in tumor tissue intratumoral vessel number / total tumor area level. The level of Ki67 was significantly decreased in the tumor tissue of the group 3. Additionally, the total necrotic area / total tumor volume (%) was decreased significantly in tumor tissue of the group 3 rats compared to group 1 and 2. CONCLUSION: The combination of hyperbaric oxygen with temozolomide produced an important reduction in glioma growth and effective approach to the treatment of glioblastoma.